Dynamics of an electron Bunch with the Uncompensated Space Charge in Plasma and Vacuum

摘要

Dynamics of an electron bunch expanding under the action of the electric force of the self-charge and the friction force in plasma and vacuum is studied in the hydrodynamic approximation. The electric field intensity, velocity, concentration, and electron bunch current are found as functions of time and distance. The moment when the velocity of electrons moving in plasma vanishes on the edge of the bunch is determined. This effect may induce back currents and result in the intersection of trajectories. It is demonstrated that parameters of an electron flow in vacuum approach their asymptotic values with time.